Spark plug



Jan. 10, 1939. BELLEMORE 2,143,048

SPARK PLUG Filed Dec. 24, 1937 Patented Jan. 10, 1939 UNITED STATES PATENT OFFICE 1 Claim.

My present invention relates to spark-plugs, and more particularly to an improved design of spark-plugs adapted to spark in a radial direction from the center ofthe inner electrode and having a continuous annular spark-gap separating the inner and outer electrode.

The principal object of my present invention is an improved spark-plug;

Another object is an improved spark-plug having a circular spark-gap separating the two electrodes;

Still another object is an improved spark-plug having an insulator core, the electrode end of which is heavy and straight sided, and

Other objects and novel features comprising the construction and operation of my invention will appear as the description of the same progresses.

In the drawing illustrating the preferred embodiment of my invention;

Fig. 1 is a side elevation;

Fig. 2 is a central cross-section takenon the line 2-2 of Fig. 1;

Fig. 3 is a side elevation of the insulator core removed from the assembly;

Fig. 4 is a plan view of the firing end of the spark-plug, and

Fig. 5 is a plan view of the terminal end of the said spark-plug.

Referring more in detail to the drawing, Ill indicates the outer shell of the spark-plug. H indicates thecentral insulated core, and I2 is a packing nut which is threaded in the outer end of the shell III, as indicated in Fig. 2. The insulator core II is provided with an enlarged mid-section 22 and is further provided with taper shoulders I3 against which bear gaskets ll when the packing nut I2 is screwed into the shell tightly, as shown in Fig. 2. The gaskets l4 prevent leakage between the shell 18 and insulator member l I.

In my present invention, it will be noted that the firing end of the insulator, as indicated at I6 is designed wtih straight sides. In other words, this portion of the insulator member is cylindrical in shape. l

At the firing end of the shell I I have provided a flange II which extends all the way around the inner opening of the saidfshell and acts as a stop for the bottom end of the insulator,

as shown in Fig. 2. At the same time this annular flange l'l constitutes one of the electrodes of the spark-plug and the space between the center electrode I 8 and the said flange ll constitutes the. spark gap. The electrode member iii in actual practice should be about one sixteenth of an inch thick and the spark-gap about twenty-five one thousandth of an inch, the drawing being exaggerated. As noted in the drawing, the electrode member I8 is attached to the central 10 electrode rod IS, in any convenient manner.

In operation, the spark passes across the circular gap between the disc l8 and the shoulder ll of the shell ID, in all directions radiating from'the electrode Hi to the shoulder l'l. Owing to the fact that the end of the insulator H is shouldered against the gap shoulder I! as well as being sealed by the gaskets It, a 'very tight joint is effected without setting the nut I2 too tight thereby eliminating some of the cause for broken insulal0 tors in actual practice.

It will be seen that with a circular gap I have increased the spark area which indirectly means quicker starting, more power the result of which is more speed and a saving of gasolene or its :5 equivalent and oil. I

While I have shown my invention somewhat in detail yet it is to be understood that I may vary the size and proportion within wide limits without departing from the spirit of the invention.

Having thus described my invention, what I claim as new. is:

An improved spark-plug comprising in combinationfan outer shell, an insulated core, nut and washers, and central electrode mounted within 5 said core, the said outer shell being provided with a cylindrical inner bore adapted to tightly enclose the firing end of said core, an annular rectangular flange located at the bottom end of said bore and adapted to receive the firing end of said 40 core, an annular recess located below said flange in said shell and extending to the extreme end of said shell, a disc having right angled sides mounted on said central electrode at the firing end of said core, said disc having a thickness equal to the combined thickness of the parallelly disposed sides of said flange and said annular recess.

k ALBERT J. BELLEMORE. 

